In an automatic winder for spun yarns, for the splicing operation, there has heretofore been adopted in which a knot is formed by using a mechanical knotter. However, recently, there is often adopted a method in which splicing is effected by entangling fibers of yarn ends by using air. This method in advantageous in that no knot is formed, the post-treatment is facilitated and a product excellent in the appearance is obtained.
Such a yarn splicing apparatus has been proposed, for example, in U.S. Pat. No. 4,263,775. But, there is a problem how an air stream is caused to act on yarn ends on splicing so as to obtain a good joint.